What is the best approach for managing a patient with severe respiratory acidosis, on BiPAP, and a DNR order?

Management of Severe Respiratory Acidosis in a DNR Patient on BiPAP

For a patient with severe respiratory acidosis (pH 7.06, PCO2 146.6) who is on BiPAP with a DNR order, continue aggressive non-invasive ventilatory support with optimization of BiPAP settings while maintaining the 88-92% oxygen saturation target. 1

Initial Assessment and Immediate Management

• Optimize BiPAP settings immediately:

  • Increase inspiratory positive airway pressure (IPAP) to 15-20 cmH2O
  • Set expiratory positive airway pressure (EPAP) at 4-8 cmH2O
  • Target respiratory rate of 12-16 breaths/min
  • Ensure proper mask fit to minimize leaks 2, 1

• Oxygen therapy:

  • Target oxygen saturation of 88-92% 2, 1
  • If using wall oxygen for nebulization, switch to compressed air-driven nebulizers with supplemental oxygen via nasal cannula at 1-2 L/min during treatments 2

Monitoring and Follow-up

• Repeat arterial blood gas within 60 minutes of adjusting BiPAP settings 2
• Look for improvement in key parameters:
  • pH (should increase toward normal)
  • PCO2 (should decrease)
  • Respiratory rate (should normalize) 2, 1
• Continue close monitoring with frequent vital signs and oxygen saturation checks
• If no improvement in 1-2 hours, reassess and adjust BiPAP settings further 2

Additional Medical Management

• Bronchodilator therapy:

  • Administer nebulized bronchodilators (β-agonist such as salbutamol 2.5-5 mg or anticholinergic such as ipratropium bromide 0.25-0.5 mg) every 4-6 hours or more frequently if needed 2
  • For severe cases, consider combination therapy with both agents 2

• Consider systemic corticosteroids:

  • Prednisolone 30 mg daily for 7-14 days if COPD exacerbation is suspected 2

• Antibiotics:

  • If infection is suspected, start appropriate antibiotics (amoxicillin or tetracycline as first-line options) 2

• Consider intravenous methylxanthines:

  • If response to other measures is inadequate, consider aminophylline infusion (0.5 mg/kg/hour) with daily monitoring of blood levels 2

DNR Considerations and Goals of Care

• DNR status does not preclude aggressive non-invasive ventilatory support 1
• Document clear parameters for continuation or withdrawal of BiPAP based on:
  • Response to therapy
  • Patient comfort
  • Goals of care 1
• Ensure the patient and family understand that BiPAP is being used as active treatment 1

Monitoring for Complications

• Watch for hypokalemia:

  • Rapid correction of severe respiratory acidosis can lead to life-threatening hypokalemia
  • Monitor potassium levels closely and supplement as needed 3

• Monitor for signs of BiPAP failure:

  • Worsening ABGs after 1-2 hours
  • Lack of improvement after 4 hours
  • Increasing respiratory rate >35 breaths/min 1

When to Consider Withdrawal of BiPAP

• If there is no improvement or worsening of physiological parameters despite optimized BiPAP settings
• If the patient is experiencing significant discomfort from BiPAP
• If goals of care shift toward comfort measures only 2, 1

Important Caveats

• There is no lower limit of pH below which a trial of NIV is inappropriate, though success rates decrease with more severe acidosis 2
• Advanced age alone should not preclude a trial of NIV 2, 1
• The presence of a DNR order does not mean that reversible causes should not be aggressively treated with non-invasive measures 1
• Avoid sodium bicarbonate therapy for pure respiratory acidosis as it lacks evidence of benefit and may have potential risks 4